package com.df.common.filter;

import com.df.common.utils.StringUtils;
import com.df.common.utils.html.EscapeUtil;
import org.apache.commons.io.IOUtils;
import org.springframework.http.HttpHeaders;
import org.springframework.http.MediaType;

import javax.servlet.ReadListener;
import javax.servlet.ServletInputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import java.io.ByteArrayInputStream;
import java.io.IOException;

/**
 * XSS过滤处理
 *
 * @author dunfeng
 */
public class XssHttpServletRequestWrapper extends HttpServletRequestWrapper {
  /** @param request */
  public XssHttpServletRequestWrapper(HttpServletRequest request) {
    super(request);
  }

  @Override
  public String[] getParameterValues(String name) {
    String[] values = super.getParameterValues(name);
    if (values != null) {
      int length = values.length;
      String[] escapseValues = new String[length];
      for (int i = 0; i < length; i++) {
        // 防xss攻击和过滤前后空格
        escapseValues[i] = EscapeUtil.clean(values[i]).trim();
      }
      return escapseValues;
    }
    return super.getParameterValues(name);
  }

  @Override
  public ServletInputStream getInputStream() throws IOException {
    // 非json类型，直接返回
    if (!isJsonRequest()) {
      return super.getInputStream();
    }

    // 为空，直接返回
    String json = IOUtils.toString(super.getInputStream(), "utf-8");
    if (StringUtils.isEmpty(json)) {
      return super.getInputStream();
    }

    // xss过滤
    json = EscapeUtil.clean(json).trim();
    final ByteArrayInputStream bis = new ByteArrayInputStream(json.getBytes("utf-8"));
    return new ServletInputStream() {
      @Override
      public boolean isFinished() {
        return true;
      }

      @Override
      public boolean isReady() {
        return true;
      }

      @Override
      public void setReadListener(ReadListener readListener) {}

      @Override
      public int read() throws IOException {
        return bis.read();
      }
    };
  }

  /**
   * 是否是Json请求
   *
   * @param request
   */
  public boolean isJsonRequest() {
    String header = super.getHeader(HttpHeaders.CONTENT_TYPE);
    return MediaType.APPLICATION_JSON_VALUE.equalsIgnoreCase(header)
        || MediaType.APPLICATION_JSON_UTF8_VALUE.equalsIgnoreCase(header);
  }
}
